This invention is directed to a small sized printer of the type having a plurality of print rings with print characters circumferentially disposed therearound, and in particular to an improved detection and control arrangement for use with a small sized printer of the type utilized in a desk calculator, for controlling the duration of print cycle and sequence of printing, during each print cycle of the printer.
Miniaturized printers, of the type utilized to provide a permanent record in a desk calculator or other computing instruments, such as a cash register or the like, are characterized by the use of a drive motor that is energized during printing, and is deenergized when the printer is not in use. When the printer is in use, a supply voltage is applied to the drive motor to effect an energization of same for a complete printing cycle of the printer, which printing cycle includes the positioning of the print rings for printing, the printing operation, and the return of the print rings to a stand-by position wherein each of the print rings are aligned in a rest position so that the next printing cycle can be commenced.
Due to the rapid speed with which the information can be processed by small sized electronic instruments, such as desk calculators and the like, it is desired that the entire printing cycle of the printer be completed at higher speeds with greater accuracy and at less expense. Heretofore, printers of the prior art have utilized two distinct detector arrangements for controlling the print cycle of the printer. A first detector was utilized to detect the position of the print rings and selectively position the print rings in the print position, whereas the second detector was utilized to detect the rotary position of gears utilized to drive the print rings, and deenergize the motor utilized to drive the printer at the end of or just prior to the end of the print cycle. Accordingly, such prior art printers required a delay subsequent to the completion of the printing cycle, thereby causing a stand-by time between each printing cycle that substantially slows down the speed of the printer. Moreover, in prior art printers, the paper upon which the information is printed is usually advanced to permit reading of the printer characters at the completion of the printing cycle.
The aforenoted disadvantages obtain in several types of small sized printers of the print ring variety. For example, a first type of printer, in which such disadvantages occur and to which the instant invention is directed, is the type of printer wherein the shafts supporting each of the print ring returns each of the print rings to a rest position after printing, thereby by rotating the shaft supporting the print rings in the opposite rotational direction, so that the print rings are returned to a rest or stand-by position after each printing cycle. A second printer is of the type where the shaft supporting the print rings is rotated through a single revolution, and within the revolution permits each of the print rings to be selectively positioned in a print position, and thereafter rotated toward a rest or stand-by position at the end of the print cycle. The third type of printer arrangement to which the instant invention is directed, is where the shaft supporting the print ring is rotated through a first revolution to position the print rings at a print position, and then through a further revolution so that the print rings are returned to the rest or stand-by position. Heretofore, the three types of printer arrangements detailed above have utilized two distinct detectors, a first detector for producing print character signals, and a second and distinct detector for producing a stop signal for controlling the drive motor. Alternatively, a signal detector was used to produce the print character signals, with a clutch being utilized to control the operation of the drive motor. Accordingly, a single detector arrangement for use in a miniaturized printer that is capable of producing print character selection signals and also producing motor control reference signals is desired.